Respiratory Flow Sensor Port Alignment for Kink-Free Pressure Sensing
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Solution Overview
Problem
Existing respiratory flow sensors suffer from issues such as kinking of connecting lines, requiring complex design and production measures, and occupy a large space due to radially projecting extension tubes, leading to inaccurate measurements and cumbersome handling.
Innovation Solution
A respiratory flow sensor design with ports aligned parallel to the longitudinal axis and connecting lines that run essentially parallel or at angles to the axis, eliminating butt joints and allowing for a compact, easy-to-produce structure using injection-molded plastic parts with grooves and comb structures for sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If connecting lines are arranged radially at ports, then pressure difference extraction is enabled, but the connecting lines can kink leading to measurement falsification
Solution Approach 1:
The connecting lines are oriented essentially parallel to the longitudinal axis of the flow tube rather than radially outward, changing the spatial dimension of connection. This axial alignment prevents kinking while maintaining pressure difference extraction capability through ports positioned at opposite ends of the flow tube.
2Measurement precision
If radially projecting ports are provided for pressure extraction, then flow measurement is enabled, but expensive design and production measures are required for sealing
Solution Approach 1:
Instead of having ports project radially from the flow tube wall, the ports are positioned at the ends of the flow tube with connecting lines running parallel to the longitudinal axis. This inverted arrangement simplifies sealing requirements while maintaining measurement functionality.
3Measurement precision
If extension tubes project radially from the flow sensor, then pressure difference extraction is achieved, but the flow sensor occupies large space and causes complicated handling
Solution Approach 1:
The extension tubes are reoriented to run essentially parallel to the longitudinal axis of the flow tube rather than projecting radially. This axial alignment allows the tubes to be positioned within the longitudinal profile of the flow sensor, significantly reducing the overall space occupation and improving handling characteristics while maintaining pressure difference extraction capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures precise measurement accuracy, prevents kinking, and allows for a compact design with straightforward assembly, reducing production complexity and space occupation.
Implementation Method 1
A respiratory flow sensor is known from U.S. Pat. No. 4,403,514 A, which comprises a flow tube which has a longitudinal axis, a first flow tube portion and a second flow tube portion and tube ports for tubes in the region of the free ends. A flow resistor is arranged in the flow tube between the first flow tube portion and the second flow tube portion. Furthermore, radially projecting ports are provided for extracting the pressure difference generated by the flow resistor.
Data Source
AI summary
The invention relates to a respiratory flow sensor (11) comprising a flow tube (12), which has a longitudinal axis (14), a first flow tube portion (21) and a second flow tube portion (41), comprising a flow resistor (61), which is disposed between the first flow tube portion (21) and the second flow tube portion (41) in the flow channel (13), and comprising two ports (32, 52) for extracting the pressure difference generated by the flow resistor (61). The first port (32) opens into the first flow tube portion (21) via a first connecting line and said first port is disposed at the first flow tube portion (21). The second port (52) opens into the second flow tube portion (41) via a second connecting line and said second port is disposed at the second flow tube portion (41). The ports (32, 52) each comprise a connecting line portion (33, 53), which extends substantially parallel to the longitudinal axis (14) of the flow tube (12). The openings (35, 55) of the ports (32, 52) are aligned in the same direction. The invention further relates to a respiration adapter and a method for producing a respiratory flow sensor (11).